Many companies and other organizations operate computer networks that interconnect numerous computing systems to support their operations, such as with the computing systems being co-located (e.g., as part of a local network) or instead located in multiple distinct geographical locations (e.g., connected via one or more private or public intermediate networks). For example, data centers housing significant numbers of interconnected computing systems have become commonplace, such as private data centers that are operated by and on behalf of a single organization, and public data centers that are operated by entities as businesses to provide computing resources to customers. Some public data center operators provide network access, power, and secure installation facilities for hardware owned by various customers, while other public data center operators provide “full service” facilities that also include hardware resources made available for use by their customers. However, as the scale and scope of typical data centers has increased, the tasks of provisioning, administering, and managing the physical computing resources have become increasingly complicated.
The advent of virtualization technologies for commodity hardware has provided benefits with respect to managing large-scale computing resources for many customers with diverse needs, allowing various computing resources to be efficiently and securely shared by multiple customers. For example, virtualization technologies may allow a single physical computing machine to be shared among multiple users by providing each user with one or more virtual machines hosted by the single physical computing machine. Each such virtual machine may be regarded as a software simulation acting as a distinct logical computing system that provides users with the illusion that they are the sole operators and administrators of a given hardware computing resource, while also providing application isolation and security among the various virtual machines.
Operators of data centers that provide different types of virtualized computing, storage, and/or other services usually rely on standard networking protocols to receive customer requests and transmit responses to such requests using commodity network hardware such as various types of network interface cards (NICs). Until a few years ago, networking configuration for virtualized computing environments was still being managed at the physical NIC level. Some network operators have recently incorporated virtual network interfaces (which may also be referred to as “elastic network interfaces”) into their infrastructure, enabling some networking-related attributes such as IP (Internet Protocol) addresses to be transferred relatively easily between virtual machines without necessarily reconfiguring physical NICs. Such attribute transfers may be accomplished, for example, by detaching a virtual network interface programmatically from one virtual machine and attaching it programmatically to another virtual machine. While easing the complexity of network configuration somewhat, however, at least some virtual network interface implementations may still not support the kinds of flexibility (e.g., in terms of the way network addresses can be dynamically re-mapped to underlying physical resources) demanded by some applications and services that are being targeted for virtual computing environments.
While embodiments are described herein by way of example for several embodiments and illustrative drawings, those skilled in the art will recognize that embodiments are not limited to the embodiments or drawings described. It should be understood, that the drawings and detailed description thereto are not intended to limit embodiments to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope as defined by the appended claims. The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description or the claims. As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words “include,” “including,” and “includes” mean including, but not limited to.